murre (mör) [key], common name for a group of diving birds of the same family as the auk and the puffin (family Alcidae) and including the guillemots. There are three species of murres, all about 18 in. (45 cm) long, brownish black above and white below. The common murre, Uria aalge, and the Brunnich's murre are found in the North Atlantic; the California murre is found in the Pacific. Murres are among the largest of the living members of the family. The smaller guillemots are also called sea pigeons. Murres eat small fish and crustaceans and lay their hard-shelled, pear-shaped eggs on bare rock. Murres return to the same breeding sites year after year. Both male and female incubate the single egg laid per season. Murres are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Charadriiformes, family Alcidae.